package 懒汉式;
 class DoubleCheck {

	private DoubleCheck() {
	}

	private static DoubleCheck dCheck;

	public static DoubleCheck getInstance() {
		if (dCheck == null) {
			synchronized (DoubleCheck.class) {
				if (dCheck == null) {
					dCheck = new DoubleCheck();
				}
			}
		}
		return dCheck;
	}

}
